JPS587995B2 - Multilayer matrix type liquid crystal display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a matrix type liquid crystal display device having orthogonal strip-shaped electrodes, a so-called matrix electrode structure, and particularly the present invention relates to the structure of the matrix electrodes.

The drive of a matrix type liquid crystal display device, for example, a line sequential scanning method, is constructed as shown in FIG.

That is, the main memory device 1 stores characters, symbols, figures, patterns, etc., and this stored data is converted into a display pattern by the character signal converter 2, and is sent to the buffer memory in the column drive circuit 3 for each row of the display screen. After storing the data in the column electrodes, the outputs thereof are supplied to the column electrodes Y1, Y2, . . . , Yn, respectively.

Row electrodes X1, Y2, etc. that intersect with one column electrode
, Xm are sequentially driven by a row driving circuit, and the information stored in the buffer memory is displayed row by row.

In the figure, numeral 5 is a control device for controlling the operations of the column drive circuit and row drive circuit, and 6 is a liquid crystal display device having matrix type electrodes.

In this matrix type liquid crystal display device, the greater the number of lines, the higher the display density and the higher the display accuracy. However, as the number of lines increases, the time for applying a signal to one line, that is, the duty, decreases, and crosstalk ( Problems such as cross effect) will occur.

Particularly when a liquid crystal is used as a display element, the threshold value as a characteristic of the liquid crystal is not steep.

Due to the slow response, sufficient contrast cannot be obtained.

In order to solve these problems, it is conceivable to make the liquid crystal a multilayer cell structure, divide the electrode distribution into front liquid crystal cells and rear liquid crystal cells, and increase the duty in each cell to prevent deterioration in display quality.

However, in the case of a multilayer cell structure, since the positions of the liquid crystal layers are different between the front liquid crystal cell and the rear liquid crystal cell, parallax occurs in the displayed pattern.

Particularly when displaying characters, etc., if different liquid crystal layers are selected within one related pattern, parallax may cause the second
As shown in the figure, the display dots overlap, making it difficult to discern the pattern.

In Figure 2, the row electrodes 19a, 19b, . . . show their apparent positions when viewed diagonally from below, and the hatched portions indicate dots to which an electric field is applied.

This phenomenon in which the display becomes difficult to see occurs particularly when viewed from diagonally above or diagonally below because the row electrodes are arranged between the front and rear cells.

Although the problem of parallax mentioned above can be improved to some extent by making the central glass 15 thinner, it cannot be made extremely thin because the mechanical strength of the central glass is required for leading out the terminals.

The present invention provides an electrode structure that improves the overlapping of display dots as described above.

In particular, considering the display content, the present invention uses row electrodes forming at least one digit as one group in the front liquid crystal cell so that a group of related electrodes such as characters can be displayed by the same liquid crystal cell. Alternatively, the electrode group is provided in the rear liquid crystal cell, and this electrode group is arranged alternately in the front liquid crystal cell and the rear liquid crystal cell to prevent the phenomenon in which display dots overlap within one digit and become difficult to see.

FIG. 3 shows a cross-sectional configuration diagram of an embodiment of the liquid crystal display device of the present invention, and in this figure, only the portion displaying two rows of digits is shown in an enlarged scale.

As can be seen from Figure 3, the front glass 13 and the central glass 1
5 constitute a front side liquid crystal cell 11, and column electrodes 14a, 14b, . . . are provided on the inner surface of the front glass 13.

A row electrode 16 is provided on the front side of the central glass 15.
If the digits are displayed in a 5x7 matrix, 7
The row electrodes 16a to 16g for the rows are set as a group, and this group is provided on the front side of the central glass 15.

Next, the center glass 15 and the rear glass 18 constitute the rear liquid crystal cell 12, and the column electrodes 17a are arranged on the back side of the center glass 15.
, 17b... are provided, and the column electrodes 17a,
17b... are the column electrodes 14a, 14b...
It is arranged so that it overlaps with...

The rear glass 18 is provided with row electrodes 19. The rear glass 18 is provided with row electrodes 19 in the number of rows of digits, for example seven rows 19h to 19n.

Thereafter, row electrodes are provided alternately in the front liquid crystal cell 11 and the rear liquid crystal cell 12 in groups of rows of one digit.

Next, the process of making the above electrode structure will be explained.

Soda glass with a thickness of 3 mm is used as the front glass 13 and the rear glass 18, and column electrodes 14 and row electrodes 19 are attached according to a known method.

Soda glass with a thickness of 0.3 mm is used as the central glass 15, and row electrodes 16 are formed on the front side and column electrodes 17 are formed on the back side through the following steps.

First, as shown in FIG.
Transparent conductive films 21 and 22 made of 2O3 or SnO2 are deposited on one surface.

Next, in order to form row electrodes on the front side, photoresist 23 (trade name: AZ-1350, manufactured by Shipley) is coated on the entire front side using a spinner at 3000 RPM.

After prebaking, exposure is performed through a photomask 24 as shown in FIG. 4C to develop the result.

Next, post-baking is performed, and in order to protect the transparent conductive film 22 on the back side, a photoresist 25 (product name: AZ-1350, manufactured by Shipley) is coated on the entire surface using a spinner.
Figure 4e).

This is pre-baked and etched (Fig. 4 f)
), the resist 25 is peeled off (FIG. 4g), and the glass substrate is cleaned.

Thus, row electrodes 16 are formed on the front side of the glass 15.

In order to form column electrodes 17 on the back side, the entire back side is coated with photoresist 26 made of the same material as above, as shown in FIG. 4h.

This is prebaked and exposed through a photomask 27 (FIG. 4i) to cause a phenomenon (FIG. 4j).
For protection, a photoresist 28 of the same material as above is coated as shown in FIG. 4k.

This is etched (Fig. 4 1), the photoresist is peeled off, the glass substrate is cleaned (Fig. 4 m), and the column electrodes are placed on the back side.
form 7.

As described above, according to the present invention, since the liquid crystal device has a multilayer structure with liquid crystal cells in the vertical direction and the electrodes are divided, the duty cycle assigned to each electrode is longer than in the case of one layer. Even if the electrode density in the pattern displayed in digits is increased, the display quality will not be impaired.

Particularly within the L digit, the display dots are formed on the same plane, so they do not overlap, and therefore do not become difficult to see as shown in FIG.

However, in the present invention, for example, the first row pattern is displayed in the first layer cell, and the second row pattern is displayed in the second layer cell, so the size of the line spacing between the first row pattern and the second row pattern However, since the line spacing is set to a predetermined size, the patterns in each line do not overlap, and therefore do not become difficult to see, making it practical. I can't stand it.

In the above embodiment, the front cells 11 and the rear cells 12 are formed alternately for each row, but the front cells 11 and the rear cells 12 are formed alternately in groups of two to several rows. You can.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a circuit that drives a matrix type liquid crystal display device, FIG. 2 is a diagram explaining the display state of a conventional device, and FIG. 3 is a configuration of a multilayer matrix type liquid crystal display device according to an embodiment of the present invention. A cross-sectional view, FIG. 4 is a process diagram illustrating the process of forming an electrode on the central glass, and FIG. 5 is a diagram illustrating a display state by the apparatus of the present invention. 11: Front side liquid crystal cell, 12: Rear side liquid crystal cell, 13:
Front glass, 14: Column electrode, 15: Center glass, 16:
Row electrode, 17: Column electrode, 18: Back glass, 19: Row electrode.

Claims (1)

[Claims] 1. In a multilayer matrix type liquid crystal display device in which a plurality of liquid crystal cells are superimposed and each liquid crystal cell is provided with a matrix electrode structure consisting of a row electrode group and a column electrode group to perform display driving, at least the rows forming a no digit (Column) electrode groups are arranged in the same liquid crystal cell as the same group, and a column (row) electrode group facing the row electrode group is arranged in the liquid crystal cell,
The row (column) electrode groups of the matrix electrode structure are divided and arranged alternately in each liquid crystal cell for each row (column) electrode group forming at least one digit. A multilayer matrix type liquid crystal display device characterized by a superimposed arrangement of groups.